This is generated by nir_lower_frexp, and if we leave fisfinite in place
then the late algebraic pass lowering it to this pattern will cause an
un-lowered fabs64 to be emitted.
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22083>